Revisiting the physical mutagenesis for sugarcane improvement: a stomatal prospective

Abstract

This study was conducted to investigate the influence of gamma rays on stomatal parameters and the interaction of these traits with agronomy of the sugarcane crop. Three genotypes of sugarcane (NIA-0819, NIA-98, and BL4) were exposed to four doses of gamma radiation (10, 20, 30, and 40 Gy) and then subjected to field trials. Stomatal length, width, and density were observed using scanning electron microscopy. Moreover, agronomic and sugar-related characteristics of the crop were determined at maturity. The stomatal parameters augmented at two lower doses of gamma radiation (10 and 20 Gy) and declined under higher doses (30 and 40 Gy). The maximum stomatal length was observed in NIA-0819 at 10 Gy (63.71 µm), whereas NIA-98 and BL4 demonstrated highest stomatal length under 20 Gy (54.11 and 57.40 µm, respectively), indicating a role of genetic factors in varietal response. Similar trend was noticed for stomatal width and density as well. The lowermost treatment (10 Gy) of NIA-0819 produced maximum stomatal density (115.31 stomata mm-2 on the abaxial surface). Adaxial stomatal density was significantly lower than the abaxial one. Sugar quality attributes revealed a different tendency. Sucrose contents of BL4 increased gradually from 12.33% at control to 14.54% at 40 Gy. Yield and yield-contributing traits of genotypes indicated a strong positive correlation with the stomatal parameters. The present study suggested that gamma radiations cause variations in stomatal characteristics of sugarcane. These changes further influence the photosynthetic activity and instigate a direct impact on the agronomic performance of the crop.

Characterization and evaluation of putative mutant populations of polyembryonic mango genotype Nekkare for dwarfing rootstock traits

“…Among the treatments, mean stomatal density decreased in lower doses viz., 15 Gy and 20 Gy of being 12.64 (per 20000 µm 2 ) and 12.43 (per 20000 µm 2 ) respectively while it increased at 25 Gy (13.3 per 20000 µm 2 ) and 30 Gy (13.85 per 20000 µm 2 ). Our results are in contrary to the findings of Yasmeen et al (2020) who reported an increase in stomatal density at lower doses of irradiation.…”

“…Gamma rays are the most widely used physical mutagen employed in mutation breeding of crop plants and are well known for bringing about morphogenetic and endomorphic changes in plants (Ali et al, 2016;Yasmeen et al, 2020). In the present study considerable variation was created for different morphological traits in the putative mutant population of polyembryonic mango genotype Nekkare generated by gamma irradiation (Table 1a and 1b…”

“…The highest (63.12 µm) and lowest (60.92 µm) mean stomatal width was recorded in population generated through 20 Gy and 25 Gy respectively. An increase in stomatal length and width was recorded in sugarcane at lower doses of gamma irradiation (10 and 20 Gy) which declined further with increased doses (30 and 40 Gy) (Yasmeen et al 2020). Similarly, a significant reduction in stomata length and number at higher doses of gamma irradiation was observed in Kinnow (Mallick et al, 2016), grapes (Kok, 2011) and mango (Rime et al, 2019).…”

“…Induced mutation has been known to create variations in plant height, growth pattern, leaf characteristics and various biological and physiological traits including stomatal size and number (Kovacs and Keresztes, 2002). Stomatal structure (including size and density) is the major plant cellular component contributing towards growth and development (owing to its role in gaseous exchange and transpiration thus directly affecting photosynthesis) of the plants besides playing a crucial role in stress tolerance (Yasmeen et al, 2020). Hence, any change in stomatal parameters resulting from mutagenesis could be highly significant.…”

Morphological, agronomical, physiological and molecular characterization of a high sugar mutant of sugarcane in comparison to mother variety

“…The callus of cultivar ROC22 was mutagenized chemically and mutant lines were found to be suitable for upcoming drought resistance breeding [ 32 ]. Three sugarcane cultivars, NIA-0819, NIA-98 and BL4, in Pakistan were subjected to mutation through gamma radiation and the obtained mutants were with altered stomatal characteristics which positively added to yield and yield related traits in sugarcane [ 33 ]. The majority of mutations have neither negative nor positive effects on the organism in which they take place such mutations are called neutral mutations.…”